DETECTOR MODULE FOR AN X-RAYS DETECTOR WITH A HEATING LAYER

Description

[0001] The invention relates to a detector module for an X-ray detector with a heating layer. Furthermore, the invention relates to an X-ray detector comprising a plurality of detector modules and to a computed tomography device comprising such an X-ray detector.

[0002] An X-ray detector is used in imaging applications. For example, such an X-ray detector is used in medical imaging for computed tomography scans to create a three-dimensional image of a patient's examination area.

[0003] X-ray detectors can be designed as counting, direct-converting X-ray detectors or integrating, indirect-converting X-ray detectors. An X-ray detector whose sensor layer is a direct-converting semiconductor layer enables the quantitative and energy-selective detection of individual X-ray quanta. Suitable semiconductor materials for detecting X-ray quanta include CdTe, CdZnTe, CdTeSe, CdZnTeSe, CdMnTe, GaAs, Si, and Ge, which exhibit a high absorption cross-section for X-rays. When X-rays strike the sensor layer, electron-hole pairs, i.e., pairs of negative and positive charge carriers, are generated. Applying a voltage to the sensor layer or its surface separates the charge carriers, causing them to move towards the oppositely charged electrodes or surfaces of the sensor layer.The resulting current or charge displacement can be evaluated by downstream sensor electronics, hereinafter also referred to as the evaluation unit or evaluation layer. The sensor layer or sensor unit of a direct-converting X-ray detector is typically arranged in a stacked configuration with its associated evaluation unit. Such a stacked configuration of sensor layer and evaluation unit can also be referred to as a sensor board.

[0004] In particular, direct-converting (photon-counting) X-ray detectors must be kept at a precise, constant temperature during operation. Otherwise, image artifacts can occur. In direct-converting X-ray detectors, or in the detector modules of a corresponding setup, the electrical resistance of the sensor material changes with the X-ray flux. This leads to a change in power dissipation. Consequently, a change in X-ray flux causes a temperature change in the sensor layer, which in turn affects the energy resolution and the count rate of the X-ray detector. In addition to time-dependent temperature changes in the sensor layer, the drift behavior of an X-ray detector is also influenced by locally varying temperatures within the sensor layer. Such temperature gradients arise primarily from uneven heat dissipation in the sensor layer.An undesirable temperature gradient can also occur on the sensor board or within the sensor layer of the respective sensor board, depending on the operating point of the sensor board. Depending on the selected operating parameters, such as the average operating temperature of the detector module or the sensor material, or the applied supply voltage, an increased current through the sensor material can occur. This can lead to high power dissipation, even without incident X-ray radiation, and thus also to a temperature gradient in the sensor layer.

[0005] To avoid temperature gradients in the sensor layer, a thermal coupling to a heat sink that is as close to the entire surface area as possible is desirable. However, achieving full-surface coupling and thus uniform heat dissipation is made more difficult by components located on the underside of the sensor board, such as passive components or connectors for data transmission that serve to connect to module electronics, and / or by other mechanical cutouts. Consequently, heat dissipation by a heat sink is highly dependent on the design of the sensor board and the geometry of the module assembly. Heating elements can also be used in the sensor board to stabilize the temperature of the X-ray detector, providing additional heating power. However, the arrangement and design of these heating elements must be adapted to any existing, potentially uneven, temperature distribution within the sensor board.

[0006] For the development of an X-ray detector, it remains desirable to develop individual components as independently as possible, avoiding premature commitment and limitations in the design process. Furthermore, it is advantageous if components can be used flexibly, for example, across different detector geometries. However, the use of costly components or manufacturing steps must always be kept to a reasonable level, which may, under certain circumstances, conflict with the aforementioned objectives.

[0007] US 2019 / 383954 A1, for example, discloses an X-ray detector with a heating layer.

[0008] The invention aims to provide an advantageously temperature-stabilizable detector module that at least partially addresses the aforementioned disadvantages and objectives. A further objective of the invention is to provide an X-ray detector and a computed tomography device with a plurality of corresponding detector modules.

[0009] The problem is solved by the features of the independent claims. Further advantageous and partly inventive embodiments and developments of the invention are set out in the dependent claims and the following description.

[0010] The invention relates to a detector module for an X-ray detector comprising in a stacked structure a sensor layer, a readout layer, a heating layer, and a wiring unit downstream of the heating layer in the stacked structure, wherein the heating layer is divided into a plurality of partial heating areas, each of which has at least one heating element and each of which can be individually contacted for a power supply, and wherein the partial heating areas of the heating layer are contacted by means of the downstream wiring unit and at least a subset of the partial heating areas are interconnected for the power supply.

[0011] The X-ray detector module according to the invention has a stacked structure. The stacking direction can, in particular, be oriented substantially parallel to the operational direction of incidence of the X-ray radiation. The sensor layer is preferably arranged closest to the X-ray source in the stacked structure, so that the X-ray radiation is incident, in particular, directly onto the converter unit.

[0012] Advantageously, the sensor layer comprises a direct-converting semiconductor material, in particular cadmium telluride (CdTe) or cadmium zinc telluride (CdZnTe). Such semiconductor materials enable the direct conversion of incident X-rays into an electrical signal and are commercially available in good quality with respect to charge transport properties and homogeneity. The sensor layer can also comprise another semiconductor material in the form of CdTeSe, CdZnTeSe, CdMnTe, GaAs, Si, or Ge. Although temperature stabilization is of particular importance in direct-converting detectors, a detector module according to the invention can also include an indirect-converting material in combination with a photodiode array and a sensor layer. Scintillators, for example GOS (Gd₂O₂S), CsJ, YGO, or LuTAG, are frequently used as the converter material in this case.

[0013] The sensor layer of a detector module can be formed in one piece. However, it can also be formed from several sensor elements arranged in a row, which together span the sensor layer.

[0014] The readout layer can, in particular, comprise a plurality of pixel electronics, each of which can be configured for the pixel-by-pixel, and thus spatially resolved, processing of the electrical signals fed into it by the sensor layer to produce a digital pixel measurement signal. That is, each such pixel electronic can at least be configured to further process an electrical signal received from the sensor layer, in particular to digitize it, for example, by means of an analog-to-digital converter (ADC). The pixel electronics can also include further switching elements, such as a signal amplifier or a comparator. For this purpose, the readout layer, or a specific pixel electronic of the readout layer, can be coupled to the sensor layer via electrically conductive connections.The electrically conductive connections between an evaluation unit and a converter unit can be designed, for example, as solder connections (e.g., bump bonds), as conductive adhesive connections, or in other ways. To minimize the impact on signal transmission between the sensor layer and the readout layer, it is advantageous to position the sensor layer and the readout layer as close as possible.

[0015] The readout layer can be implemented as one or more readout chips in the form of an integrated circuit (IC). Each readout chip then provides pixel electronics for the primary processing of the electrical signals from the sensor layer. In particular, the readout layer can comprise one or more application-specific integrated circuits (ASICs), which are collectively encompassed by the readout layer of the detector module.

[0016] The readout layer can comprise a housing in which one or more such readout chips are encased. Alternatively, one or more such readout chips can be potted as so-called unencased "bare dies" (also "bare chip") with a potting compound, for example, a casting resin, to form a component.

[0017] The heating layer encompassed by the stack of the detector module is thermally coupled to the sensor layer within the stack. It covers at least part of the stack's surface area in a projection plane perpendicular to the stack. This coverage by the heating layer can be understood as the provision of multiple heating elements across the area covered by the heating layer, enabling the introduction of heating power, i.e., heat, into the stack via this surface. In preferred embodiments, the heating layer extends over at least the majority of the sensor layer's surface area. By covering a large portion of this surface area, the heating layer advantageously enables the introduction of heating power and thus temperature stabilization across the entire covered surface area.The larger the area covered, the more advantageous the introduction of heating power. In particularly advantageous embodiments, the heating layer, in a projection plane perpendicular to the stack structure, essentially covers the entire surface area of ​​the sensor layer. The heating layer can be thermally coupled to the sensor layer, particularly via the readout layer. In this case, it is advantageous if the readout layer, comprising a possible housing or at least partial encapsulation with a potting compound, extends in the projection plane perpendicular to the stack structure over at least the majority of the sensor layer's surface. This allows the introduction of heating power into the sensor layer via the readout layer over the largest possible area.

[0018] The heating layer incorporates heating elements designed to introduce heat into the stack structure when powered by a power unit during operation. This heat input contributes to temperature stabilization of the detector module and, for example, counteracts temperature gradients within the stack structure or sensor layer. The heating elements can be simple heating resistors or conductor loops enclosed by the heating layer. These loops can be embedded in or applied to a non-conductive material, particularly a plastic. The non-conductive material could, for example, be a printed circuit board material or the housing or potting compound of the readout layer. The heating elements of the heating layer can be arranged essentially within a single plane.

[0019] Each heating zone within the heating layer covers a portion of the layer's surface area. In other words, each heating zone covers a portion of the total surface area of ​​the stack structure covered by the heating layer. Each heating zone contains a heating element which, when supplied with power, heats the respective area of ​​the stack structure covered by that heating zone. Each heating zone can be individually connected for power supply. This means that each heating zone has contact points that allow the respective heating element within that zone to be supplied with power. For example, the heating layer is divided into more than three heating zones, specifically, for instance, 9, 16, or 25.

[0020] The division into partial heating zones provides a spatial resolution primarily achievable through the heating layer, allowing the heating power to be locally adjusted within the stack structure by controlling or supplying power to the partial heating zones differently. The greater the number of partial heating zones, the more precisely the heating power distribution can be adjusted by means of the heating layer and subsequent wiring unit. The division can be uniform, meaning that the partial heating zones can each cover an equally sized area and be arranged regularly across the surface of the heating layer. In particular, the partial heating zones of the heating layer can be identical, meaning they are designed to deliver the same heating power under the same boundary conditions and with the same power supply. They can, in particular, comprise identical heating elements.However, they can also cover different areas and / or be arranged irregularly. A largely uniform arrangement or similar design can, however, represent an advantageously simple implementation, as it keeps complexity to a minimum.

[0021] In the detector module according to the invention, a wiring unit is located downstream of the heating layer, via which the partial heating areas are contacted for power supply. The wiring unit is located downstream of the heating layer in the stack structure in that it is arranged downstream of the heating layer along the direction of radiation incidence in the operating sequence. In the stack structure, the wiring unit follows directly after the heating layer.

[0022] If the wiring unit is positioned directly on top of the heating layer in the stacked configuration, the contact points of the heating layer and the corresponding mating contact points on the wiring unit can be directly connected, for example, by means of a solder joint. In other configurations, suitable conductors are provided for the electrically conductive connection between the heating layer and the wiring layer. Furthermore, the wiring unit has conductor tracks for supplying power to the partial heating areas. The wiring unit can have essentially the same surface area as the heating layer. At a minimum, the wiring unit has a surface area sufficient to allow contact with the points of the partial heating areas.

[0023] The wiring unit remains a separate component of the detector module from the heating layer, thus enabling independent manufacturing and adaptation of the wiring unit, which is only contacted with the heating layer when the detector module is assembled. The wiring unit can be implemented as a printed circuit board (PCB) in a preferably cost-effective and simple variant. However, a design in the form of a ceramic substrate with corresponding conductive traces or similar is also conceivable.

[0024] In addition to wiring the partial heating zones of the heating layer, the wiring unit can also serve as a carrier unit for the stack arrangement and / or as a substrate for signal transmission from the readout layer of the detector module to downstream module electronics, or vice versa. Appropriate lines designed for signal transmission can be provided in the wiring unit for this purpose.

[0025] The wiring unit connects at least a subset of the heating zones for power supply. This connection involves linking the heating zones of the subset via suitable cables. This can involve a parallel and / or series connection of the heating zones. Typically, there are several subsets, with the heating zones of each subset interconnected. Each subset can then be connected to a common power supply unit via the wiring unit to power the detector module. Additional cables can be provided for operating the heating layer, leading from the wiring unit to one or more power supplies, each configured to supply power to the heating zones connected to them via the wiring unit.

[0026] The interconnection of the partial heating zones is based on the consideration that, as a rule, the detector module contains partial heating zones which, during operation, have a similar or identical heating power requirement to other partial heating zones of the detector module, or whose heating power requirement is in a fixed ratio to one another. The appropriate interconnection of these partial heating zones using the wiring unit makes it possible to supply them with power together. This contributes to a particularly cost-efficient operation of the detector module, since a separate heating circuit with its own power unit is not required for each individual partial heating zone, which would entail considerable wiring effort and require many expensive power units for power supply, thus avoiding a need for extensive cabling and a large amount of space.The implementation of a subdivided heating layer and a downstream wiring unit enables the provision of a heating layer in the detector module that is as generically designed and universally applicable as possible. Its subdivision allows for adaptation to specific conditions. This heating layer is primarily independent of other components of the detector module, such as the arrangement of connectors for data transmission or the design of a subsequent heat sink or module carrier, and can therefore be designed and implemented in a stacked configuration independently of these components. Adaptation to the specific heating power requirements of the detector module for the most cost-effective control and power supply is then achieved by connecting the sub-heating zones via the wiring unit.With this implementation, the detector module can be adapted relatively easily and cost-effectively to specific, potentially changed conditions even at a later stage of the design and development phase, simply by modifying the wiring unit of the detector module. Furthermore, the design of the detector module is easily transferable across different detector types. For example, a highly generic unit consisting of a sensor layer, readout layer, and heating layer can be provided for various detector geometries with differently designed heat sinks and wiring configurations. This unit can then be adapted to the actual distribution of heating requirements using the wiring unit. The wiring unit, for example in the form of a printed circuit board, is inexpensive and easy to provide and adapt.

[0027] The wiring of the partial heating zones via the wiring unit is advantageously adapted to the heating power requirement in the stack structure, particularly the planar distribution of the heating power requirement in a projection plane perpendicular to the stack structure. This can be measured, for example, during the operation of a preliminary detector module, or calculated and / or simulated based on known geometries and arrangements, such as the design of a heat sink intended for the detector module. Based on such considerations and calculations, a suitable wiring configuration can be derived and implemented.

[0028] The wiring of the partial heating zones via the wiring unit can include parallel and / or series connections of partial heating zones. In particular, those partial heating zones that correspond to areas of the stack structure with the same heating power requirement can be interconnected in such a way that they can be connected to a common power supply. In practical implementations, this can involve connecting those partial heating zones of the heating layer that correspond to areas of the stack structure with the same heating power requirement in parallel. These can then be connected to a common power unit for a uniform power supply and control. However, a series connection of partial heating zones is also possible.

[0029] In a further development, the wiring unit can connect at least a subset of the partial heating zones to a combination of parallel and series connections, ensuring a fixed ratio between the partial power outputs in each zone when power is supplied. This allows partial heating zones assigned to areas of the stack structure with varying heating requirements to be connected to a common power supply. Depending on the specific wiring configuration, fractions of the total power provided by the power unit may be available as partial power in the individual zones.By means of a suitable combination of parallel and series connections of partial heating zones via the wiring unit, a relative ratio of the heating power achieved in each of the interconnected partial heating zones can be defined when they are supplied by a common power unit. This is advantageous when such a defined ratio also takes into account the heating power requirements of the stacked configuration. With favorable geometric conditions, the number of power units required for operating the detector module and the wiring effort can be further reduced. In particular, several partial heating zones can be present, with at least one of these zones being connected using a combination of parallel and series connections. Other zones can be connected solely via parallel or series connections.

[0030] The detector module can, in particular, comprise a number of power units, with each power unit supplying a subset of heating zones interconnected via the wiring unit. The number of power units depends on the number of interconnected heating zones. The power unit(s) can be arranged on an electronic unit separate from the stack, for example, a printed circuit board, with suitable leads running from the stack to the power units. A separate electronic unit can advantageously provide sufficient space for arranging the power units, while the stack itself can be kept as compact as possible. This facilitates the stacking of multiple units to increase the detection area and, if necessary, optimize heat dissipation.This also makes it easier to replace individual components in case of a defect.

[0031] In advantageous embodiments, the power supplied by a respective power unit to the connected partial heating zones is based on an expected and / or measured temperature within the stack structure. This allows the heating power requirement within the stack structure, and thus the necessary heating power, to be advantageously coordinated, and the respective power unit to be controlled accordingly. In particular, a temperature profile during operation or various operating parameters and / or environmental parameters of the detector module can be advantageously taken into account. Specifically, this can include measuring and / or calculating a temperature distribution in a projection plane perpendicular to the stack structure, and possibly also its temporal profile or its dependence on various operating and / or environmental parameters.The power supplied by each power unit is estimated and adjusted or controlled based on the temperature distribution. Advantageously, the power supplied by each power unit is adapted to the heating power requirements of the sub-heating areas assigned to that power unit. An expected temperature or temperature distribution can be based on measurements taken prior to the operation of the detector module. Alternatively, it can be based on calculations or simulations. Particularly preferably, the adjustment or control of the power supplied by each power unit is based on a measured temperature or temperature distribution within the stacked configuration. Advantageously, direct temperature information can be used for adjusting or controlling the power units.In particular, each power unit can have a control circuit and be designed to regulate a supplied power based on a temperature in the stack structure.

[0032] According to one embodiment, at least one temperature sensor is arranged within the stack structure. This allows for advantageous power adjustment or control based on at least one measured temperature value within the stack structure, taking the currently measured temperature into account. In advantageous embodiments, several temperature sensors are arranged within the stack structure, enabling improved spatial resolution of the current temperature distribution in a projection plane perpendicular to the stack structure. Based on this, the control and / or regulation of the power supplied in the partial heating zones can be implemented. Alternatively, for example, an expected temperature distribution in a projection plane perpendicular to the stack structure can be derived based on a single temperature measurement.Such an implementation can involve first measuring and / or simulating the expected temperature distribution within the stacked structure during operation of the detector module, in conjunction with a measured temperature value. Based on the measured temperature value and the derived expected temperature distribution, the control and / or regulation of the heating power in the partial heating zones can then be implemented. In a particularly advantageous embodiment, the at least one temperature sensor is integrated into the readout layer.

[0033] In advantageous embodiments of the detector module, the heating layer is applied to a surface of the readout layer or integrated into the readout layer. Positioning the heating layer as close as possible to the sensor layer is advantageous, since the sensor temperature is the crucial parameter for image quality. Furthermore, placing the heating layer on a surface of the readout layer or integrating it into the readout layer is a simple design option, as the necessary heating elements and wires can be easily integrated and applied. The heating elements of the heating layer can, for example, be embedded in a housing or casing of the readout circuits of the readout layer, or applied to a surface of such a housing or casing. The heating elements of the heating layer can be in the form of heating resistors or...Heating loops may be formed, which are applied to a surface of the readout layer or integrated into the readout layer. For easy contacting of the heating elements of the heating layer by a subsequent wiring unit, it can be particularly advantageous to position the heating layer on or at the side of the readout layer facing away from the sensor layer. This can also be beneficial for the least possible interference-free transmission of signals from the sensor layer to the evaluation layer.

[0034] Furthermore, the stacked structure of the inventive detector module can be arranged on a module carrier, which is thermally coupled to the sensor layer via the stacked structure. The module carrier can be designed to mechanically fix a respective detector module within a device comprising the detector module. For this purpose, appropriate fixing and alignment means can be provided on the module carrier. The module carrier is preferably designed as a metallic heat sink, which enables heat dissipation from the stacked structure, and in particular from the sensor layer, to stabilize the temperature of the detector module. The wiring of the heating layer is then specifically adapted to the design of the module carrier and thus to areas with varying heat dissipation efficiency, resulting in a more uniform temperature distribution within the stacked structure.

[0035] Advantageously, the wiring unit in the stacked configuration is connected to the module electronics via the module carrier. The module electronics can be used for reading, collecting, and / or further processing the measurement data from the readout layer. For this purpose, the module electronics can include additional active or passive components configured to provide the necessary functionalities. Furthermore, the module electronics can be used for transmitting control data and supplying power for the operation of the stacked configuration.

[0036] In particular, the number of power units for supplying power to the heating layer can be managed by the module electronics. The module electronics typically offer sufficient space for arranging the power units. Nevertheless, it is advantageous to position the power units relatively close to each stacked structure. This also facilitates the replacement of individual components in case of a defect.

[0037] Furthermore, according to one embodiment, the detector module can comprise a number of stacked structures arranged adjacent to one another on the module carrier. For example, the detector module can include two, three, or four identically designed stacked structures. Advantageously, a larger overall detection area of ​​the module can be achieved by arranging the stacked structures in series. The multiple stacked structures can be assigned to a common module electronics unit and powered or controlled via this unit. The power supply to the heating layer of each stacked structure is preferably controllable or regulated independently of the others.

[0038] This allows for consideration of potentially different boundary conditions of the stacked configurations, such as a one-sided air supply for cooling the detector module. In this case, cooling air flows along the detector module and heats up. Consequently, the sensor layer of a sensor board located at the beginning of the cooling air path of a detector module is cooled more than the sensor layer of a sensor board located at the end of the cooling path.

[0039] The invention further relates to an X-ray detector for capturing images of an object irradiated by X-rays, comprising a plurality of detector modules arranged adjacent to one another according to one of the previously described variants. The number of detector modules used in an X-ray detector, and thus the number of sensor boards, depends on their size and the required total sensor surface area. The X-ray detector can include further elements, for example, support structures for arranging the detector modules, cooling air inlets and outlets for improved heat dissipation from the detector modules, or a scattering grating arranged in the direction of radiation incidence in front of the sensor layer of the detector modules.

[0040] All embodiments previously described in connection with the detector module according to the invention can also be implemented in the X-ray detector. The description given with regard to the detector module and the advantages of the detector module described above can accordingly be transferred to the X-ray detector according to the invention.

[0041] In particular, the invention further relates to a computed tomography device comprising an X-ray detector as described above. In contrast, the computed tomography device comprises an X-ray source configured to expose the X-ray detector to X-rays. The X-ray source and X-ray detector are arranged on a rotor, which enables rotation about an axis of rotation. The computed tomography device can also include more than one X-ray detector.

[0042] To acquire a computed tomography image data set, an object to be imaged is usually placed along the axis of rotation between the X-ray source and the detector unit and irradiated by the X-ray source.

[0043] Furthermore, features described in relation to different embodiments of the invention can be combined to form further embodiments. In addition to the embodiments of the invention expressly described in this application, numerous other embodiments are conceivable which a person skilled in the art can arrive at without leaving the scope of the invention defined by the claims.

[0044] The use of the indefinite articles "a" or "an" does not preclude the possibility that the characteristic in question may be present multiple times. The use of the expression "to exhibit" does not preclude the possibility that the terms linked by the expression "to exhibit" may be identical. For example, the computed tomography device exhibits the computed tomography device. The use of the expression "unit" does not preclude the possibility that the object to which the expression "unit" refers may have several components that are spatially separated from one another.

[0045] The invention is explained below with reference to exemplary embodiments and the accompanying figures. The representation in the figures is schematic, highly simplified, and not necessarily to scale. They show: Fig. 1 an exemplary design of a detector module for an X-ray detector with a plurality of stacked structures arranged side by side, Fig. 2 a stacked setup of an exemplary detector module, Fig. 3 a schematic illustration of a heating layer with a plurality of partial heating areas of an exemplary detector module, Fig. 4 a supervisor's view of an exemplary modular support structure, Fig. 5 a schematic illustration of a spatial distribution of heating power requirements in a stacked structure, Fig. 6 a schematic illustration of the wiring of the majority of partial heating areas of an exemplary detector module according to a first variant, Fig. 7 a schematic illustration of the wiring of the majority of partial heating areas of an exemplary detector module according to a second variant, and Fig. 8 a computed tomography scanner.

[0046] Figur 1 Figure 1 shows an exemplary embodiment of a detector module 1 for an X-ray detector. The embodiment shown comprises a plurality of identically designed, adjacent stacked structures 5. However, a detector module according to the invention can also be designed differently. For example, a detector module 1 according to the invention can also comprise only one stacked structure 5. A stacked structure 5 comprising a sensor layer 11, an evaluation layer 17, a heating layer 2 (not explicitly shown here for clarity), and a wiring unit 19, as it can be used in a detector module 1 according to the invention, is described below with reference to the Figur 2 will be explained in more detail.

[0047] In the case of the in Fig. 1 In the exemplary detector module 1 shown, the stacked structures 5 are arranged on a metallic module carrier 7. These are further connected via the module carrier 7 to a module electronics unit 15, from which outgoing data lines 16 run to the respective stacked structures 5, called sensor boards. The module electronics unit 15 can be used for reading, collecting, and / or further processing the measurement data from the readout layer 19. The module electronics unit 15 can also be used for transmitting control data and supplying power for the operation of the stacked structure 5. In particular, a number of power units 31 for supplying power to the heating layer 2 of a respective stacked structure 5 according to the invention can be included in or arranged on the module electronics unit 15. The module electronics unit 15 generally provides sufficient space for the arrangement of the power units 31.Furthermore, the sensor surface 13 of each stacked assembly is covered by a collimator 12, which serves to generate a parallel beam path and to avoid scattered radiation.

[0048] The module carrier 7 continues to serve as a heat sink for dissipating heat from the stack structures 5. The module carrier 7 is thermally coupled to the sensor layer 11 of a respective stack structure 5 via the stack structure 5.

[0049] One embodiment of a stacked structure 5 of a detector module 1 according to the invention, as is also the case for a module as in Fig. 1 It can be encompassed in Fig. 2 A more detailed illustration follows. The stack structure 5 comprises the sensor layer 11 with the sensor surface 13. The sensor layer 11 serves to detect X-rays. For this purpose, a high voltage is applied to the sensor surface 13 via an electrode (not shown) when the layer is installed within an X-ray detector. In preferred embodiments, the sensor layer comprises a direct-converting semiconductor material, in particular cadmium telluride (CdTe) or cadmium zinc telluride (CdZnTe).

[0050] The stack assembly 5 further comprises a readout layer 17. In the detector module 1 shown, the sensor layer 11 of the readout layer 17 is applied. Electrically conductive connections, for example solder connections in the form of so-called "bump bonds", are provided between the readout layer 17 and the sensor layer 11 (not shown here), which enable signal transmission between the sensor layer 11 and the readout layer 17.

[0051] The readout layer 17 can, for example, comprise one or more application-specific integrated circuits (ASICs), which are enclosed in a package. Alternatively, one or more such readout chips can be encapsulated as so-called unpackaged "bare dies" (also "bare chip") with a potting compound, such as a casting resin, to form a single component.

[0052] The stack assembly 5 further comprises a heating layer 2 and a wiring unit 19 located downstream of the heating layer 2 in the stack assembly. In the example shown, the heating layer 2 is applied to a surface of the readout layer 17. The heating layer 2 can be applied to a housing or casing of the readout layer 17 using a potting compound. In alternative versions, however, the heating layer can also be integrated into the readout layer 17, for example, into a housing. The heating layer 2 has heating elements 27 in the form of heating resistors or conductive loops, which are designed to introduce heating power into the stack assembly 5 when it is supplied with power during operation by means of a power unit 31. The heating resistors can, for example, be applied directly to the housing or casing of the readout layer 17 or, alternatively, be embedded in it in a layered manner.

[0053] In the illustrated embodiment, the heating layer 2 is thermally coupled to the sensor layer 11 in the stack structure 5 via the readout layer 17. According to an advantageous embodiment, it covers the entire surface area of ​​the stack structure 5, and thus also that of the sensor layer 11, in a projection plane perpendicular to the stack structure 5. Extending the heating layer 2 over at least the majority of the surface area of ​​the sensor layer 11 is advantageous because it allows heating power to be introduced via the heating layer 2 over the entire covered surface area, thereby stabilizing the temperature. However, embodiments are also possible in which complete surface coverage is not achieved.

[0054] Heating layer 2 is, as in Fig. 3 As indicated by way of example, the system is subdivided into a plurality of partial heating areas 101, 102, ... 116, each of which has at least one heating element 27 (shown here only in partial heating area 102) and each of which can be individually contacted for power supply. For this purpose, each heating element 27 of a partial heating area 101, 102, ... 116 has contacts 29, via which the respective heating element 27 of the partial heating area 101, 102, ... 116 can be supplied with power.

[0055] Each partial heating area 101, 102, ... 116 of the heating layer 2 covers a partial area of ​​the surface area of ​​the heating layer 2 in Fig. 2 This means that a partial heating area covers a portion of the total area of ​​the stacked structure 5 covered by the heating layer 2 and is designed to heat this area when the heating element 27 is supplied with power. In the illustration shown, the partial heating areas 101, 102, ... 116 are uniformly and identically designed. However, other configurations are possible. For example, different sized areas can be covered by a single partial heating area. In particular, the heating elements 27 can also differ from one another.

[0056] The wiring unit 19 connects the partial heating zones 101, 102, ... 116 of heating layer 2 for power supply, and at least a subset of these zones are interconnected for power supply. Interconnection involves linking the partial heating zones of the specified subset via suitable conductors. Each subset can then be connected to a common power supply unit 31 via the wiring unit 19 for the operation of the detector module 1. The wiring unit 19 provides conductor tracks for supplying power to the partial heating zones 101, 102, ... 116.

[0057] The interconnection can comprise a parallel or a series connection of the partial heating zones of the subset. In particular, those partial heating zones which are assigned to surface areas of the stack structure 5 with the same heating power requirement can be interconnected in such a way that they can be connected to a common power unit 31 and supplied with power together. An interconnection of at least one subset of the partial heating zones by means of the wiring unit 19 can also comprise a combination of a parallel and a series connection of partial heating zones of the subset, so that, when supplied with power, the interconnection establishes a fixed ratio between the partial powers present in the respective partial heating zones. Typically, several subsets are present, whereby the partial heating zones of each subset are interconnected and can be supplied with power together.

[0058] The wiring unit 19 in the exemplary stacked configuration 5 in Fig. 2 This follows directly onto the heating layer 2, so that the contact points 29 of the heating layer and the respective mating contact points provided on the wiring unit 19 can advantageously be contacted directly, for example by means of a solder connection. However, other configurations are also conceivable.

[0059] In addition to wiring the partial heating areas 101, 102, ... 116 of heating layer 2, the wiring unit 19 can also serve as a carrier unit for the stack arrangement and / or as a sub-paste for signal transmission from the readout layer 17 of the detector module to downstream module electronics or vice versa. For this purpose, appropriate lines designed for signal transmission can be provided in the wiring unit 19.

[0060] The wiring unit 18 can be further connected to subsequent components via a connector 18 and cables 16. For example, cables can be provided for the operation of the heating layer 2, leading from the wiring unit 19 to one, or possibly several, power units 31, which are designed to supply power to partial heating areas 101, 102, ... 116 connected to them via the wiring unit 19.

[0061] Based on Fig. 4 und 5 The aim is to illustrate a possible dependence of the heating power requirement in the stacked structure 5 of a detector module 1 on a mechanical design of a module carrier 7 for the detector module 1. Fig. 4 Figure 1 shows a top view of the geometric design of a module carrier 7, as it can be used for a single stack assembly 5. In this configuration, the module carrier has recesses 22 for a plug connection 18 to the stack assembly 5 and / or for data lines 16 from the stack assemblies 5 to downstream module electronics 15. As a result, the stack assembly 5 does not rest fully on the module carrier 7, leading to uneven heat dissipation from the stack assembly 5 by the module carrier 7.

[0062] Fig. 5 Figure 1 shows a possible resulting spatial distribution of the heating power requirement in the projection plane perpendicular to the stack structure 5 when it is placed on such a module carrier 7. In the areas 25, which correspond to the areas of the recesses 22, only a small amount of heat dissipation takes place. Therefore, the heating requirement is low. A significant amount of heat is dissipated via the central web of the module carrier; consequently, the heating requirement is high in area 23.

[0063] The heating requirement at the lateral supports or areas 21, for example, can lie between the two extremes.

[0064] A generic heating layer 2 according to the invention, as used, for example, in Fig. 2 As schematically illustrated, the expected distribution of heating power requirements can be advantageously adapted to such an expected distribution by means of suitable wiring via the wiring unit 19 in order to ensure cost-efficient provision and operation of the detector module 1. Similarly, a stacked structure 5 with a generic heating layer 2 could also be adapted to other mechanical designs of the module carrier 7 in a relatively simple manner, simply by modifying the wiring unit 19, thereby ensuring the closest and most advantageous arrangement of the heating layer 2 relative to the sensor layer 11.

[0065] Fig. 6 and 7 The diagram shows exemplary wiring of the partial heating areas 101, 102, ... 116 of a heating layer 2 of a detector module 1 using the wiring unit 19, when these are configured as shown in Fig. 2 The wiring diagrams shown for the partial heating areas 101, 102, ... 116 take into account an assumed distribution of the heating power requirement in the stacked structure 5 as shown by Fig. 5 This is illustrated. However, this is purely an example. Other versions may have different wiring configurations, adapted to the specific conditions.

[0066] Fig. 6 The diagram shows several partial heating zones, each connected in parallel to a power unit 31 on a module electronics via the wiring unit. The first partial heating zone comprises zones 101, 104, 113, and 116. The second partial heating zone comprises zones 102, 103, 114, and 115. The third partial heating zone comprises zones 105 to 112. Each partial heating zone connected to a single power unit 31 receives the same power. This configuration allows each partial heating zone to be supplied with power according to its heating requirements, thus requiring fewer power units 31, which is more cost-effective.

[0067] Under favorable geometric conditions, the number of required power units 31 can be further reduced by a suitable combination of series and parallel connection of partial heating zones 101, 102, ... 116. By connecting at least a subset of the partial heating zones 101, 102, ... 116 via the wiring unit, comprising a combination of a parallel and a series connection, a fixed ratio between the partial powers present in the respective partial heating zones can be established when power is supplied by a common power unit 31. Fig. 7 Figure 1 shows an example where the partial heating zones 101, 104, 113, and 116, as well as the partial heating zones 105 to 112, are connected to a common power unit 31 by means of a combination of series and parallel connections. In this configuration, partial heating zones 101, 104, 113, and 116 each receive 1 / 16 of the power of the other partial heating zones 105 to 112 from the same power unit 31. Naturally, the feasibility of such a connection depends on the expected distribution of the heating power demand and its temporal profile, insofar as the fraction of power supplied is fixed by the wiring and therefore no independent, e.g., time-variable, adjustment is possible within the interconnected subset of partial heating zones.

[0068] In advantageous embodiments of a detector module 1 according to the invention, as described above with reference to the figures, the power supplied by a respective power unit 31 for the partial heating zones connected to it is based on an expected and / or measured temperature in the stack structure 5. In particular, a temperature profile during operation or the temperature under various operating parameters and / or environmental parameters of the detector module 1 can advantageously be taken into account. This can particularly include measuring and / or calculating or estimating a temperature distribution in a projection plane perpendicular to the stack structure 5 and, if applicable, also its temporal profile or its dependence on various operating and / or environmental parameters, wherein the power supplied by a respective power unit is set or controlled based on the temperature distribution.Advantageously, the power output of a power unit 31 can be adapted to the heating power demand of the partial heating areas assigned to that power unit 31. For temperature measurement, this can be done in particular, as also shown in... Fig. 2 As indicated, at least one temperature sensor 30 is arranged in the stack structure. In advantageous embodiments, several temperature sensors 30 are arranged in the stack structure so that a current temperature distribution in a projection plane perpendicular to the stack structure can be recorded with improved spatial resolution based on measured values. Based on this, control and / or regulation of the power provided in the partial heating zones can be implemented. In a particularly advantageous embodiment, the at least one temperature sensor 30 is integrated into the readout layer.

[0069] Fig. 8Figure 1 shows an exemplary embodiment of a computed tomography device 32 with an X-ray detector 36 comprising at least one detector module 1 according to the invention and an X-ray source 37, in comparison to the detector module 36. The X-ray source 37 is configured to expose the X-ray detector 36 with X-rays. The X-ray source 37 and the X-ray detector are enclosed by a gantry 33 and arranged on a rotor 35. The rotor 35 is rotatable about the axis of rotation 43. The object 39 under examination, here a patient, is positioned on the patient table 41 and is movable along the axis of rotation 43 through the gantry 33. A processing unit 45 is used to control the computed tomography device 32 and / or to calculate cross-sectional images or volume images of the object. A reconstruction device 45 in the form of a computer system is configured to reconstruct X-ray image data based on the data from the X-ray detector 36 of the computed tomography device.Another computer system serves as an operator console 47. The software installed on the operator console 47 enables the operator to control the operation of the computed tomography device, such as selecting a protocol, starting the scan, etc. The reconstruction device 45 and the operator console 47 can also be configured as a single computer system.

[0070] The X-ray detector 36 of such a medical imaging device 32 can in particular comprise one or more detector modules 1. In particular, the detector modules 100 are then usually arranged next to each other, at least in the direction of rotation, so that by arranging the respective detection surfaces of the detector modules 100 in succession, an advantageously large total detection area can be formed.

Claims

1. Detector module (1) for an X-ray detector (36) comprising in a stacked structure (5) a sensor layer (11), a readout layer (17), a heating layer (2), and a wiring unit (19) which is positioned directly after the heating layer (2) in the stacked structure and is embodied as a separate component from the heating layer (2), wherein the heating layer (2) is partitioned into a plurality of heating subregions (101,102,...,116), each of which comprises at least one heating element (27), and with each of which contact can be made individually for supplying power, wherein each heating subregion (101,102,...,116) of the heating layer (2) has contact points (29) for the supply of power, and wherein by means of the wiring unit (19) arranged after, contact is made to each of the heating subregions (101,102,...,116) of the heating layer (2), by contact being made between the contact points (29) of the heating layer (2) and respective mating contact points provided on the wiring unit (19), and at least one subset of the heating subregions (101,102,...,116) is interconnected for the supply of power.

2. Detector module (1) according to claim 1, also comprising a number of power units (31), wherein the at least one subset of the heating subregions (101,102,...,116) that is interconnected via the wiring unit (19) is connected to a shared power unit (31) for the supply of power.

3. Detector module (1) according to one of the preceding claims, wherein the interconnection of the at least one subset of the heating subregions (101,102,...,116) by means of the wiring unit (19) comprises a parallel connection of at least two of the heating subregions (101,102,...,116) or a series connection of at least two of the heating subregions (101,102,...,116).

4. Detector module (1) according to one of the preceding claims, wherein the interconnection of the at least one subset of the heating subregions (101,102,...,116) by means of the wiring unit (19) comprises a combination of a parallel connection and a series connection of heating subregions (101,102,...,116) of the subset, so that, when power is being supplied to the subset of the heating subregions (101,102,...,116), the interconnection sets a fixed ratio between the sub-powers present in the respective heating subregions (101,102,...,116).

5. Detector module (1) according to claim 2, wherein the power provided by a particular power unit (31) for the heating subregions (101,102,...,116) connected thereto is based on an expected and / or measured temperature in the stacked structure.

6. Detector module (1) according to one of the preceding claims, wherein at least one temperature sensor (30) is located in the stacked structure.

7. Detector module (1) according to one of the preceding claims, wherein the heating layer (2) is applied to a face of the readout layer (17) or integrated in the readout layer (17).

8. Detector module (1) according to one of the preceding claims, wherein the wiring unit (19) is embodied as a printed circuit board.

9. Detector module (1) according to one of the preceding claims, wherein the sensor layer (11) comprises a direct converting semiconductor material, in particular cadmium telluride (CdTe) or cadmium zinc telluride (CdZnTe).

10. Detector module (1) according to one of the preceding claims, wherein the stacked structure (5) is located on a module carrier (7), which is thermally coupled to the sensor layer (11) via the stacked structure (5).

11. Detector module (36) according to one of the preceding claims, wherein the wiring unit (19) in the stacked structure (5) is connected to a module electronic circuit (15) via the module carrier (7).

12. Detector module (36) according to claim 11 in combination with claim 2, wherein the number of power units (31) are comprised by the module electronic circuit (15).

13. Detector module (1) according to one of claims 10 to 12, having a number of stacked structures (5) located adjacent to one another on the module carrier (7).

14. X-ray detector (36) for acquiring images of an X-rayed object (39), comprising a plurality of adjacently located detector modules (1) according to one of the preceding claims.

15. Computed tomography device (32) comprising an X-ray detector (36) according to claim 14 and an X-ray source (37) opposite thereto, wherein the X-ray source (37) is designed to shine X-ray radiation onto the X-ray detector (36).